Hi,
Support cpu microcode loading for AMD CPUs with NetBSD/amd64,
NetBSD/i386 and NetBSD/Xen.
Get the microcode patch from http://www.amd64.org/support/microcode.html
and put the extracted microcode_amd.bin file into
/libdata/firmware/x86/amd/
Then run cpuctl identify 0 and you should see something like this:
cpu0: UCode version: 0x1000080
After applying the microcode patch with
'cpuctl ucode'
you can see with cpuctl identify 0 that the patch got applied:
cpu0: UCode version: 0x1000083
The patch is a draft for review/comments and not yet for committing.
For x86 I need to make use of xc_broadcast(9) to apply the microcode
on all cpus.

kauth(9) is implemented as requested from tls@ and also
uses xc_broadcast(9) to automatically apply the ucode patch on all cpus.
This version is intended to get committed. Please review.
Christoph